Phthalazine derivatives



United States Patent 3,274,185 PHTHALAZINE DERIVATIVES Max V. Sigal, Jr., Gayton, England, Paolo Marchini, Charlottesville, Va., and Buford L. Poet, Bristol, Tenn., assignors to The S. E. Massengill Company, Bristol, Tenn.

No Drawing. Original application Oct. 8, 1963, Ser. No. 314,640. Divided and this application May 3, 1965, Ser. No. 462,162

6 Claims. (Cl. 260-440) This is a division of our copending application Serial No. 314,640, filed October 8, 1963, now abandoned, for Phthalazine and Quinazoline Derivatives.

The present invention relates to new phth-alazine derivatives, and more particularly to such derivatives having a high degree of activity as antidepressants so that the compounds can be used as tranquilizers with a sedative action and as blood pressure depressants.

It is the primary object of the present invention to provide a new series of substituted phthalazines.

It is another object of the present invention to provide a new series of compounds having sedative-tranquilizing action and blood pressure depressant action.

It is yet another object of the present invention to provide for the production of the new substituted phthalazines of this invention.

It is yet another object of the present invention to provide for the method of achieving antidepressant action.

Other objects and advantages of the present invention will be apparent from a further reading of the specification and of the appended claims.

With the above and other objects in view, the present invention mainly comprises substituted 2,3-benzodiazine compounds of the formula:

wherein Y and Y are selected from the group consisting of hydrogen, lower alkyl, lower alkoxy, halogen and methylenedioxy, wherein Z is selected from the group consisting of phenyl, lower alkyl-substituted phenyl, halogen-substituted phenyl, lower alkoxy-substituted phenyl, benzyl, lower alkyl-substituted benzyl, lower alkoxy-su-bstituted benzyl, lower alkyl, thenyl, cyclopentyl, cycloheptyl, 3',4-methyleneoxyphenyl, 3',4-rnethylenedioxy benzyl, amino, hydrazino, mercapto and hydroxyl, and wherein R is selected from the group consisting of hydrogen, hydroxyl, halogen, amino, lower alkylamino, methyleneamino, methylene-lower alkylamino, methyleneaminotrimethylene-lower dialkylamine, hydrazino, benzylhydrazino and lower alkoXy-substituted benzylhydrazino.

Referring more specifically to Formula I above, Y and Y may be hydrogen, lower 'alkyl such as methyl, ethyl, propyl and the like, lower alkoxy such as methoxy, ethoxy, isopropoxy and the like, halogen such as chlorine, and methy-lenedioxy.

In Formula I, Z is most preferably:

Phenyl,

Benzyl,

Thenyl,

p-tolyl,

p-chloro phenyl, 3',4-dirnethoxy benzyl, 3',4'-diethoxy benzyl, methylendioxy benzyl, Cyclopentyl, or Cycloheptyl 3,274,185 Patented Sept. 20, 1966 In Formula I above, R is most preferably: Hydroxyl, Chlorine, Hydrogen, 1 Amino,

Substituted amino such as: CH NH (methylenamino), -CH -N CH 2 (methylendimethylamino) CII N(lower alkyl) and CH NHCH CH CH N(CH Hydrazino or NHNR', wherein R (HI -CH The compounds of the present invention have been found to have a primary action as sedative-tranquilizers and blood pressure depressants. It is possible to achieve an anti-depressant action by administering the compounds of the present invention to patients requiring the same.

In addition, the compounds of the present invention have also been found to have a potent antihistaminic activity.

The substituted 1,3-benzodiazine compounds of Formula I above can be produced by reacting the substituted phenylacetic acid with the chosen substituted phthalic anhydride to give a substituted benzal phthalide which is reacted with hydrazine to form the corresponding phthalazone. Replacement of the hydroxyl in l-position is accomplished in the usual manner with POCl The corresponding phthalazine is produced by catalytic reduction at room temperature.

Direct reaction of the compound in which R is chlorine with hydrazine or ammonia results in the production of the corresponding hydrazine or amino substituted phthalazine.

In the case wherein Z is cycloalkyl, the condensation of the cycloalkylhalide and magnesium with the chosen substituted phthalic anhydride results in the corresponding phthalide which is further reacted as described above.

The following examples are given to further illustrate the present invention. The scope of the invention is not, however, meant to be limited to the specific details of the examples.

EXAMPLE 1 OCH | OCH;

a period of two hours. The reaction is maintained at 240 C. until the distillation of water ceases. 'lhe flask is cooled to 90-95 C. and the crude product crystallized from absolute ethyl alcohol to yield '34 g. (M.P. 132- 13'3 C.). I w

Calc. for C1'7H1404Z C, 72.32; H, 4.95. Found: C, 71.80; H, 4.99.

EXAMPLE 2 OOHa 1-(3',4-dimeth0xybenzyl) '4-hydr0xy phthalazine 3',4'-dimethoxybenzalphthalide (35 g.) are dissolved in ethyl alcohol '(200 ml.) with hydrazine (12 ml.). The mixture is refluxed for four hours, cooled, and allowed to stand overnight. The crystalline product is filtered and recrystallized :from absolute ethyl alcohol to yield 34.5 g. (M.P. 193194 C.).

Calc. for C H N O C, 68.93; H, 5.40; N, 9.46. Found: C, 68.22; H, 5.24; N, 9.20.

EXAMPLE 3 OCHQ H, 1-(3,4'-dimeth0xybenzyl) -4-chl0r0phthalazine EXAMPIJE 4 NHNH,

| HaCO- 4 1 (3 ',4 -dimeth0xy benzyl-4-hydrazin0-6,7-dimeth0xy phthalazine 1-(3',4-dimethoxy) benzyl-4-chloro-6,7 dimethoxy phthalazine (6 g.) is added to ethyl alcohol (50 ml.) containing hydrazine (25 m1.) and refluxed for ten hours. The mixture is cooled overnight at 4 C. The precipitate is collected by filtration and recrystallized from absolute methanol to yield 2 g. (M.P. 112 C., recrystallized at C., final M.P. 178-179 C.).

Calc. for C H N O .CH OH: C, 59.86; H, 6.20; N, 13.96. Found: C, 60.04; H, 6.31;N, 13.65.

EXAMPLE 5 H300 OCH;

OC a

1 (3 ',4 dimethoay benzyl-6,7-dimeth0xy phthalazine l-(3,4'-dimethoxy)benzyl-4-chloro 6,7 dimethoxy phthalazine (2 g.) in ethyl alcohol (280 ml.) containing potassium hydroxide (0.82 g.) is hydrogenated in the presence of palladium on charcoal, 5% catalyst (2 g.). After the reaction is complete, the mixture is filtered and evaporated in vacuo. 30% sodium hydroxide (2 ml.) is added and the mixture extracted with benzene. The benzene extract is concentrated in vacuo to 1.5 ml. and ethyl ether (2 ml.) is added. The resulting white precipitate is filtered and crystallized twice from ethyl acetate petroleum ether (2:1) to yield 0.9 g. (M.P. 120- 121 C.).

Calc. for C H O N C, 67.07; H, 5.87; N, 8.23. Found: C, 67.48; H, 5.79; N, 8.12.

EXAMPLE 6 moomoo- 6,7-dimeth0xy-L4-dihydroxy phthalazine m-Hemipenic anhydride (10 g.) is combined in ethyl alcohol ml.) with hydrazine (5 g.) and refluxed for twelve hours. After cooling, the white material is dissolved in dilute ammonium hydroxide. The clear solution is acidified with hydrochloric acid. The resulting precipitate is collected by filtration and recrystallized from glacial acetic acid to yield 8 g. (M.P. 333-335 C. dec.)

Calc. for H H N O C, 54.06; H,4.50; N, 12.61. Found: C, 54.04; H, 4.23; N, 12.30.

EXAMPLE 7 H3CO- C H N O 6,7-dimeth0xy-I-methyl-4-hydr0xy phthalazine M.P. 249259 C. d. Theory: C, 60.28; H, 5.01;, N, 12.78. Found: C, 59.72; H, 5.33; N, 12.73.

V 3, 274, 18 5 5 6 EXAMPLE 8 EXAMPLE 12 O H NBC-N: (7- C H:

COOH HaCO I 5 N N H CO- v a a 0 (|)CH.'. C H N O 1- (3',4'-diethoxybenzyl) -4-hydroxy- 15 1 -pyruvilidene-2-(1 '-3",4"-dimeth0xybenzyl-6',7'-

phthalazine dimethoxyphthalazinyl hydrazine M.P. 249-259 c. d. Theory: c, 60.28; H, 5.01; N, 12.78. Found: c, 59.72; H, 5.33; N, 12.73.

EXAMPLE 9 C19H19N2C102; 1-(3',4'-dieth0xybenzyl) -4- chlorophthalazine M.P. 102 C. Theory: C, 66.56; H, 5.59; C1, 1034; N, 817. Found: C, 67.21; H, 5.79; Cl, 10.12; N, 7.85.

EXAMPLE 10 NHNH2 OCH;

| OCH C H N O 1-(3',4'-dimeth0xybenzyl) -4-hydrazin0 phthalazine M.P. ISO-152 C. Theory: C, 65.81; H, 5.80; N, 18.06.

EXAMPLE 11 @A N 1 I +112 C H N O 1 (3 ',4 -dieth0xybenzyl ph thalazine M.P. 125-127 C. Theory: C, 74.03; H, 6.48; N, 9.09. Found: C, 73.76; H, 6.07; N, 9.32.

solution is concentrated to one-third volume.

1 (3',4 dimethoxybenzyl) 4 hydrazino 6,7 dimethoxyphthalazine (2 g.) and pyruvic acid (0.45 g.) are dissolved in ethyl alcohol ml.) and refluxed for 12 hours. The solution is evaporated to dryness, and the residue recrystallized from absolute methanol to yield 0.7 g. (M.P. 210215 C., dec.).

Calc. for C22H26N406: C, H, N, Found: C, 60.52; H, 4.48; N, 12.66.

EXAMP LE 13 OH CH NHN=OH N JH2OH U l CH5 OCHs OCH

EXAMPLE 14 NH-N=CH 0011. OCH;

OCH:

| OCH: 1 (3 ,4 ',5 -trimeth oxybenzylidene -2- (3 ",4 "-dimethoxybenzyl)phthalazinyl hydrazine 1-(3,4',-dimethoxybenzyl) 4-hydrazino phthal-azine (1.5 g.) and 3,4,5-trimethoxybenzaldehyde (1.0 g.) in ethyl alcohol ml.) are refluxed for two hours. The

The re- 7 sulting precipitate is collected and recrystallized twice from ethyl alcohol to yield 1 g. (MJP. 159-160 C.).

Calc. for C H N O C, 66.36; H, 5.79; N, 11.46. Found: C, 66.14; H, 5.84; N, 10.86.

The pharmacological activity of the compounds of the present invention is illustrated in the table below:

4. 1-pyruvilidene-2-(1'-3",4" dimethoxybenzyl 6',7'- dimethoxyphthalazinyl) hydrazine.

5. 1-(2-methyl-3-hydroxy 5-hydroxymethyl)pyridylene-2-(3',4-dimethoxybenzyl phthalazinyl) hydrazine.

6. 1-(3',4',5' tr-imethoxybenzylidene) 2-(3",4"-dimethoxybenzyl)phthalazinyl hydrazine.

Hypotensive Activity, Muscle Bath, Coronary di- Adrenolytie Ae- Hypertensive Animals Muscle Bath, GI ileum- Intact Rabbit latlon, Langen- Chart #1 tivity, Dog Rat ileun1 Diphenhydra- Histamine, 1 mg./ dorff Prepare Atropine, l. mine, 1. kg. lv.-Protective ti0nRabhit Dog Cat: Rat dose heart. Papavorine, 1.

1-(3, 4-dimethoxybenzyl)-4- 0003 025 5 mgJkg. iv 1 hydrazine phthalazine. 1 mgJkg 1 mgJkg. 1v.

4-pheny1-2-hydroxyquinazoline 05 025 5mg./kg. iv 2 1 mgJkg. 1v 1 mgJkg. 1v.

Sleeping Time, Pento- Decrease Reserpine De- Ohart #2 Conditioned Avoidancebarbital Potentiationpression in Rats and Mice Rats Mice 1-(3, 4'-dimethoxybenzyl)-4 /kg.+50%

hydraziuo phthalazine. 5 mgJkg. 1v 10 mgJkg. 1p

4-phenyl-2-hydroxy quinazoline 10 mg./kg.+%

5 rug/kg. iv 1p -1 UNITED STATES PATENTS 10/ 1949 Hartman et al. 260--250 12/1961 En-gelbrecht et al. 260-250 OTHER REFERENCES Aggarwall et al.: Journal Chemical Society, 1930, pp.

References Cited by the Examiner 'Druey et al.: Journal of Medicinal and Pharmaceutical 40 Chemistry, vol. I, No. 1 (1959), pp. 1-7.

ALEX MAZEL, Primary Examiner.

HENRY R. JILES, Examiner.

JAMES H. 'IU-RNIPSEBD, Assistant Examiner. 

3. 6,7-DIMETHOXY-1,4-DIHYDROXY PHTHALAZINE.
 6. 1-(3'',4'',5'', - TRIMETHOXYBENZYLIDENE) - 2-(3",4"-DIMETHOXYBENZYL) PHTHALAZINYL HYDRAZINE. 